Allowing a young child to leave the safety of a home or other secure area without adult knowledge or supervision exposes the child to dangerous conditions. For example, the child may wonder off, become lost, hit by a car, bit by a dog or wild animal and even being kidnapped. Therefore, it is believed that there is a need for a safety door, door lock and door lock release mechanism for preventing a child from opening a door, window or the like while allowing an individual to do the same without undo interference.
Problems of a similar nature have been recognized. For example a U.S. patent of Bryll, No. 4,189,708 discloses a method and apparatus for controlling access to a facility. As disclosed, the system denies unauthorized access to a locked facility by a person having a weight characteristic differing from that of the weight characteristic of the person locking the facility. The system comprises a method and apparatus which may be selectively activated to measure a deflection caused by a person locking a facility. The system comprises a method and apparatus which may be selectively activated to measure a deflection caused by a person seated in a vehicles driver's seat. The deflection is weight information which is stored. A person subsequently seated in the vehicle seat and attempting to operate the ignition causes a second measuring operation and a comparison of the newly measured weight information with the stored information to test for a substantial parity there between. A substantial parity of these weights allows operation of the starting motor of a vehicle while a disparity between the weights operates a timer and/or alarm means while disabling the vehicle starter motor.
The system may be used to control access to various other kinds of lock facilities such as locked rooms or buildings.
A more recent patent of Parcvuescu, No. 6,081,758 discloses a system for automatically unlocking an automobile child safety door lock. As disclosed, the system includes an emergency sensor such as a collision sensor initiating airbag deployment, a door lock mechanism and a door lock releasing mechanism. Upon the sensor detecting an emergency such as a collision, the sensor produces a signal that is sent to the door lock releasing mechanism. The door lock releasing mechanism then unlocks the door. The sensor may also trigger disconnection of the battery from the automobile's electrical circuitry and interruption of the fuel line from the fuel tank to the engine. The emergency sensor may alternatively include a temperature or smoke sensor.
A further patent of Talbot, No. 6,206,452 discloses a vehicle having an automatic child lock function that is controlled by an electronic control unit. The electronic control unit receives signals from weight sensors in the base portion of each of the passenger seats. The findings from the sensors are used to determine both the occupancy of the vehicle and to produce a signal indicative of the weight of each of the passengers of the vehicle. The electronic control unit is programmed to operate such that if the signal received from a particular sensor indicates that the passenger is below a predetermined weight which indicates that the passenger is probably a child, the associated door is prevented from being opened from a closed position even when an interior door handle is operated by the passenger.
However, none of the above mentioned patents directly address the problem of a child leaving a secured area as for example a home without knowledge or supervision of an adult.
None of the patents address the problem of allowing an adult to use a door without the need to unlock a door while preventing a child from leaving through the same door. None of the patents disclose a method and system for warning an adult that a child is attempting to leave the security of the house or automatically warning a parent or supervisor of a dangerous condition and at the same time automatically releasing a door lock permitting a child to leave the house in the event of a fire or other dangerous condition.
Accordingly, it is presently believed that there is a need and a potential commercial market for a safety door, door lock and door lock release mechanism in accordance with the present invention. There should be a commercial market because such safety doors, door lock and door lock releasing mechanism prevent a child from opening the door while allowing an adult to do so.
A further advantage of the safety door, door lock and door lock release mechanism resides in the use of a weight sensor and height sensor and in one embodiment a switch for actuating the program that is disposed at a height above the reach of a child. Further, the safety door, door lock and door lock release mechanism include means for entering pre-selected weights and heights into a memory so that an individual can select the weight and height needed to actuate the release of the lock by the door lock release mechanism.
It is also believed that a system in accordance with the present invention can be manufactured and sold at a reasonable price, are reliable and durable. A still further advantage of the present invention resides in the ability to install the door lock release mechanism in a door jam adjacent to the door. This allows installation of an electrical circuit without requiring a flexible connection to allow for the opening and closing of the door. A further advantage of the present invention resides in the use of a door alarm system wherein the second alarm, which indicates a dangerous condition, provides a louder and more visual alarm.